1. Field of the Invention
This invention is in the field of devices for converting rotary motion to reciprocating motion.
2. Description of the Prior Art
The prior art is repleted with various schemes for converting rotary to reciprocating motion, and vice versa. Such schemes have been necessary since at least the invention of the steam engine. In a steam locomotive engine, for example, it is necessary to convert the reciprocating motion of the pistons to the rotary motion of the drive wheels. For a piston-type compressor driven by a rotating motor (such as an electric motor) one must convert the rotating motion of the motor to the reciprocating motion of the compressor piston. As a matter of fact, almost all internal combustion engines, witht the exception of turbine and other rotary types, must convert reciprocating to rotary motion to provide power for their intended use. The usual manner of converting reciprocating to rotary motion (and vice versa) consists of a crankshaft, with a crank thereof connected by a connecting rod to a piston pin carried by a piston. A different arrangement may be employed if one is concerned solely with converting from rotary to reciprocating motion. This arrangement consists of a crankshaft or camshaft rotated by some means, a crankarm or cam carried by such shafts, a yoke arranged for reciprocating motion in a yoke guide as with a slot in the yoke into which the crankarm or cam fits, and a connecting rod between the yoke and the part to be reciprocated. This type of arrangement is seen not only in compressors, but in such devices as hedge clippers, hay mowers, and power looms. All of the above-described arrangements have disadvantages. In the case of the crankshaft, connecting rod, and piston pin arrangement, one has a massive (compared to piston mass) forged connecting rod requiring two journals. Moreover, the rod has a complex motion difficult to balance. In the case of a crankarm or cam in a slotted yoke, the slots have heretofore had straight sides, usually being rectangular, oval, or square. The only yoke not having such straight side of which the instant inventors are aware is shown in U.S. Pat. No. 21,911 of Oct. 26, 1858, wherein the yoke has a slot with curved sides between straight ends. None of the prior art converters are able to obtain the motion which is obtained by the instant invention; specifically, rotary motion is converted to a sine wave reciprocating motion.